The typical loading dock includes one or more loading bays, each having a doorway which can be enclosed by an overhead door. In most loading docks, a dock leveler is mounted in the floor of the dock at each loading bay, and with a truck backed up to the loading bay, the dock leveler is operated to span the gap between the dock floor and the bed of the truck, so that material handling equipment, such as a fork lift truck, may conveniently move between the dock floor and the truck bed.
In many instances the overhead doors may be open or elevated when there is no truck at the loading bay. The dock floor is normally elevated above the driveway up to about 48 inches, and a fork lift truck maneuvering on the dock floor may accidentally back through the dock opening or doorway and fall onto the driveway, causing possible injury to the fork lift truck operator and/or damage to the equipment.
To prevent the accidental fall of material handling equipment or other objects through the doorway at the loading bay, it has been proposed to install safety gates at the loading bay to obstruct the doorway when the overhead door is in the elevated or open position. In order to withstand potential impact from a fork lift truck the gate must necessarily have substantial size and weight. One form of safety gate that has been utilized in the past, is mounted on the inside of the dock wall and one end of the gate is pivoted to a supporting post or column, so that the gate can be pivoted between a vertical storage position and a horizontal obstructing position. A second form of safety gate that has been employed in the past is mounted for vertical movement on a pair of vertical columns that are mounted on either side of the doorway in the loading bay. Due to the weight of the gate, which may be up to several hundred pounds, the gate is motor driven between the upper storage position and the lower operative position.
There has been a need for an inexpensive, lightweight, manually operated safety gate that is capable of withstanding substantial impact, if accidentally contacted by material handling equipment.